A. I. Blair D. P. Hampshire
We investigate the in-field critical current density Jc(B) of superconducting-normal-superconducting (SNS) Josephson junctions (JJs) and polycrystalline superconducting systems with grain boundaries modeled as Josephson-type planar defects, both analytically and through computational time-dependent Ginzburg-Landau (TDGL) simulations in two and thre…
Preprint PublishedM.A. Van Zeeland W.W. Heidbrink R.K. Fisher M. García Muñoz, G.J. Kramer D.C. Pace R.B. White S. Aekaeslompolo M.E. Austin J.E. Boom I.G.J. Classen S. Da Graça B. Geiger M. Gorelenkova N. N. Gorelenkov A. W. Hyatt N. Luhmann M. Maraschek G. R. McKee R. A. Moyer C. M. Muscatello R. Nazikian H. Park S. Sharapov W. Suttrop G. Tardini B. J. Tobias Y. B. Zhu DIII-D and ASDEX Upgrade Teams
Neutral beam injection into reversed magnetic shear DIII-D and ASDEX Upgrade plasmas produces a variety of Alfvénic activity including toroidicity-induced Alfvén eigenmodes and reversed shear Alfvén eigenmodes (RSAEs). These modes are studied during the discharge current ramp phase when incomplete current penetration results in a high central sa…
PublishedG. J. Kramer R. Nazikian B. Alper M. De Baar H. L. Berk G.-Y. Fu N. N. Gorelenkov G. Mckee S. D. Pinches T. L. Rhodes S. E. Sharapov W. M. Solomon M. A. Van Zeeland JET EFDA Contributors
Reversed shear Alfvén eigenmodes RSAE that were observed in the Joint European Torus (JET) [P. H. Rebut and B. E. Keen, Fusion Technol. 11 , 13 (1987)] and DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] are studied with the ideal magnetohydrodynamic code NOVA-K C. [Z. Cheng, Phys. Rep. 211 , 1 (1992)]. It was found that the frequency behavior …
PublishedS. E. Sharapov B. Alper J. Fessey N. C. Hawkes N. P. Young R. Nazikian G. J. Kramer D. N. Borba S. Hacquin E. De La Luna S. D. Pinches J. Rapp D. Testa JET-EFDA Contributors
A microwave interferometry technique is applied for the first time for detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas of the Joint European Torus. The interferometry measurements of plasma density perturbations associated with ACs show an unprecedented frequency and time re…
PublishedG. J. Kramer S. E. Sharapov R. Nazikian N. N. Gorelenkov R.V. Budny
Experimental evidence is presented for the existence of the theoretically predicted odd toroidicity induced Alfve?n eigenmode (TAE) from the simultaneous appearance of odd and even TAEs in a normal shear discharge of the joint European torus. The modes are observed in low central magnetic shear plasmas created by injecting lower hybrid current driv…
PublishedR. Nazikian G. J. Kramer C. Z. Cheng N. N. Gorelenkov
The original description of alpha particle driven instabilities in the Tokamak Fusion Test Reactor in terms of toroidal Alfven eigenmodes (TAEs) remained inconsistent with three fundamental characteristics of the observations: (i) the variation of the mode frequency with toroidal mode number, (ii) the chirping of the mode frequency for a given toro…
Published